1. Field of the Invention
This invention relates to a column and more particularly to a column with one or several trays, in which there is a seal between the trays and the wall of the column.
2. Description of the Prior Art
Columns with trays are known and commonly in use in industry. Normally there is a space between the periphery of the tray and internal surface of the wall of the tower. It is known to prevent the passage of matter through the separation between a column wall and column internals, especially trays, by means of seals in the manner of a piston ring seal, which while not completely blocking off such space, will at least reduce the passage of matter therethrough. Under normal operating conditions, such seals are satisfactory but are not satisfactory in columns which are exposed to corrosive fluids and are operated at an elevated temperature. The number of usable sealing materials for these extreme conditions is very small, since many sealing materials are operative only at a relatively low temperature and only a small part of the temperature-resistant materials withstand fluids with strongly corrosive action. Materials with good resistance, such as polytetrafluoroethylene (PTFE) or other synthetic fluorine materials and graphite, on the other hand, have substantially less compressibility than sealing materials of the elastomer type and are, therefore, not suitable to compensate for the relatively large installation clearances which may maximially be up to 8 cm and are necessary for columns operated at higher temperatures.